The removal of hydrogen sulfide and other sulfur species from hydrocarbon fluids and aqueous streams in oil and gas production and refining is important because of the many safety and environmental hazards posed by the presence of such species.
For example, during combustion, sulfur-rich hydrocarbon streams produce heavy environmental pollution. Further, when sulfur-rich streams contact metals, sulfur species lead to brittleness in carbon steels and to stress corrosion cracking in more highly alloyed metals used in oil and gas production and refining operations. Moreover, hydrogen sulfide in various hydrocarbon or aqueous streams poses an environmental hazard if the hydrogen sulfide in these streams is released into the air or water sources.
Triazine and glyoxal are two of the most widely used hydrogen sulfide scavengers. However, using these compounds often results in the formation of oligomeric and polymeric sulfur-containing structures that instigates deposit build-up in the system. Removal of these solids may be difficult and oftentimes results in lost operational time. For example, use of triazines can result in the formation of dithiazines, especially at colder conditions. Triazines react quickly in aqueous environments but disperse poorly in crude oil conditions, thus slowing down reaction kinetics. In crude oil conditions, triazine is spent at a very high level where amorphous dithiazine will most likely form. Thus, in many applications the use of nitrogen-containing additives such as triazines and other amines is undesirable.
Thus, generally sulfur, in the form of H2S, is an undesirable contaminant in many hydrocarbon streams and volumes having hydrocarbon carbon chain lengths of from C1 to C30, some of which may be utilized as or in fuels containing hydrocarbon molecules having C1-C12.
Future gasoline specifications in the United States require sulfur compounds to be reduced to very low levels. The levels are low enough that gasoline blend components such as butanes containing sulfur compounds will make the finished gasoline fail sulfur limits. Refiners desire to limit their capital expenditures and seek alternatives to the building of additional hydrotreating capacity, so they are seeking alternatives to remove these sulfur compounds from their distillates.
It would be desirable to remove sulfur compounds from refinery distillate streams and other hydrocarbon and/or hydrogen streams and volumes using an alternative process to those presently in use.